Bearings utilized in pulleys, sheaves and like rotating mechanisms may be held in position about the center or rotational axis of the mechanism in various ways. One common method of holding a bearing or the like involves a press fit construction wherein the bearing is pressed into an opening provided in the center of the rotatable mechanism. When plastic materials are utilized in this construction, a considerable amount of material is required for strength and to prevent premature failure. In addition, separate seals and shields must be provided in the bearing to contain lubricants and to prevent the entrance of contaminating materials.